The CCM feednecks you can find on eBay for ICD are the correct threading. All the ones they display you need an allen wrench to tighten though. I believe you might be able to get clamping rings for them in the future. (or right now)
I put an Empire clamping for Ion threads on my Promaster years back. I loctited it in place and it's been fine. From what I remember it screwed on okay. Although it's been found that Ion threads not exactly the same as ICD threads and aren't guaranteed to fit. Still, it might be something to try as long as you don't tighten it on too much and strip out your body. Here's the link to that Empire feedneck.